Tape-confined inductive element



p 1964 E. c. RECHEL TAPE-CONFINED INDUCTIVE ELEMENT 2 Sheets-Sheet 1 Filed Sept. 6, 1960 awn/day Sept. 15, 1964 E. c. RECHEL TAPE-CONFINED INDUCTIVE ELEMENT 2 Sheets-Sheet 2 Filed Sept. 6, 1960 United States Patent O 3,149,297 TAPE-CQNFINED INDUCTEVE ELEMENT Edwin C. Rachel, 85 Lancaster Road, Shirley, Mass. Filed Sept. 6, 1960, Ser. No. 5 %,062 6 Claims. (Cl. 335-209) This invention relates to a tape-confined inductive element, and, more particularly, to a wound coil form such as is employed in communication work, either with or without an iron core.

Current electronic installations utilize hosts of random wound inductors. Hence, the emphasis has been on economical manufacture. The forms or tubes on which the wire was wound usually took one of two forms. In one aspect, the tube was equipped with end flanges to provide a spool or bobbin wherein the end flanges confine the random Wound winding. In the other aspect, insulating layers were interposed between winding layers to provide a flange-less, self-supporting, wound coil form. It will be appreciated that the windings had to be confined or supported in some manner to prevent accidental contact with other conductors. The previously-employed expedients were not only uneconomical, but posed problems during the actual winding due to potential human errors.

It is an object of this invention to provide a wound coil form and method of making the same which overcomes the diiiiculties outlined above.

Another object is to provide a unique wound coil form of the random wound type and which is self-supporting without the need of the usual integrally attached flanges or the interpositioning of insulating, support-providing layers.

Still another object is to provide a random wound coil form and method of making in which a tubular spool is employed in conjunction with lengths of adhesive-equipped tape, or the like, and wherein the tape and spool cooperate in a novel manner to support the windings both during fabrication and subsequent thereto.

Other objects and advantages of the invention may be seen in the details of construction and operation set down herein.

The invention will be explained in conjunction with an illustrative embodiment in the accompanying drawing, in which FIG. 1 is a fragmentary perspective view of an arbor employed for winding coil forms and in which the various winding elements are partially assembled;

FIG. 2 is a fragmentary elevational view of the arbor having winding elements assembled thereon prior to a Wire-winding operation;

FIG. 3 is a sectional view, taken along the line 3-3 of FIG. 2;

FIG. 4 is a View similar to FIG. 2 but with the elements in a further condition of fabrication;

FIGS. 5, 6 and 7 are views essentially similar to FIGS. 2 and 4, but in which the winding operation is seen in successively progressive steps;

FIG. 8 is a fragmentray perspective View of an arbor with the winding elements partially disassembled therefrom;

FIG. 9 is an end elevational view of a wound coil form after removal from the arbor, the coil form also being seen in FIG. 8;

FIG. 10 is an enlarged sectional view, taken along the line 101@ of FIG. 9;

FIG. 11 is a view similar to FIG. 10 but in which the wound coil form is seen in its completed state;

FIG. 12 is a side elevational view of a spacer employed in connection with the arbor as seen in the preceding views and which shows additional details of construction; and

FIG. 13 is an end elevational view of the spacer seen in FIG. 12.

In the illustration given, the numeral 26 designates an arbor or mandrel adapted to be mounted in a winder for rotation about the arbors longitudinal axis. A winderengaging fitting is seen at 21, and reference to FIGS. 1 and 2 reveals that the arbor is ensleeved alternately with spacers 22 and coil forms or tubes 23. The spacer 22 can also be seen in FIGS. 12 and 13 in greater detail.

Inasmuch as the spacers can be reused, they are desirably constructed of metal such as aluminum or steel, and are contoured for various operations to be performed during the winding of the coil forms or tubes 23.

The tubes 23 may assume a variety of sha es other than the square shape illustrated, although this form is preferred for many electronic installation, since it permits the ready receipt of a laminated iron core. The forms 23 also may be constructed of a variety of insulating materials, i.e., plastics, etc. However, it has been a general practice to spirally wind webs of impregnated paper or other cellulosic material for this purpose.

In the operation contemplated, the spacers 22 and tubes 23 are alternately assembled on the mandrel 20 as seen in FIG. 2. In some instances, end flanges such as are designated 22' in FIG. 4, may be also employed. Thereafter, a length of tape 24 (see FIGS. 4 and 5) is adhesively secured in conforming relation with the spacers 22 and tubes 23. Excellent results are obtainable with commercial adhesive tapes wherein the tape is equipped with one adhesive side, and the adhesive side is positioned adjacent the mandrel or arbor Zil-as contrasted to the remote side. For the purpose of implementing the securement, the spacers 22 are recessed or grooved as at 25 (see FIG. 3), and the recesses 25 serve as a guide for the laying down of the strips of adhesive tape 24. As will be brought out later, the recesses 25 are stepped as at 25a to accommodate a wider superposed tape. It will be noted that the width of tape 24 is such that the tape overlaps adjacent corners of the tube.

After the tapes 24 have been installed as seen in FIG. 4, the tubes are wound to the condition designated or shown schematically at 26 in FIG. 5. The winding 25 comprises a length of electrical conduit, usually of small diameter, random wound on each tube 23. During this operation, the sides of the inserts 22 serve as temporary flanges or confining shoulders so that there is no tendency of the tape 2 in the portions 24a thereof to bow outwardly. Alternatively, the flanges 22' may be employed, the conduit urging the tape 24 against these flanges. It will also be noted that the sides of the spacers are recessed as at 22a to accommodate end portions 23a (see FIG. 10) of the tubes 23 and thus preclude the conduit winding 26 from entering between the spacer and tube.

Following the winding operation, a second length of tape 27 (see FIG. 6) is superposed on the tape 24, resting on shoulders 25a. The width of this tape is designated B in FIG. 8 and it is seen that the tape effectively will cover the corners of the form or tube 22.

Thereafter, the superposed tapes 24 and 27 are trans-- versely severed by means of a knife or other cutting tool (see FIG. 7) in the vicinity of an annular groove 29 in each insert or spacer 22. When this step is performed, the assembly can be dismantled to provide the elements seen in FIG. 8 where the arbor is again designated generally by the numeral 20 and the tube or core is designated 23. In FIG. 8, the winding 26 is seen to have assumed a generally cylindrical shape, although with a smaller winding there will be pronounced corners corresponding to the shape of the tube or core 23. The ends of the winding 26 are designated by the numerals Za and 26b, and, in accordance with contemporary practice, these ends may be coupled as by soldering to suitable lead-in connections or other lug-equipped fixtures.

The inner tape 24 is seen to have its intermediate portion 24b (see FIG. 7) secured to the tube or coil form 23 with portions 2% extending laterally of the axis of the coil form. Still further, the severed tape 24 is seen to be equipped with an end portion 24c which extends parallel to the intermediate portion 24b.

Correspondingly, the tape 27 is equipped with end portions 27a which overlie and are attached to the portions 24c (see FIG. 10), and a central or intermediate portion 27b which overlies and is secured to the winding 26. In the operation, the overlying end portions 240 and 27a are folded down into contact with the portion 24a, as seen in FIG. 11. Inasmuch as both the tapes 24 and 27 are positioned with their adhesive sides adjacent the core 23, the end portion 27a is readily secured to the end portion 24c-when single faced adhesive tapes are employed, the adhesive surface occurs on the end portion 27a, while the adjacent portion 24c of the inner tape is plain. However, the portions 24c and 24a of the inner tape 24, when they are brought together in the configuration seen in FIG. 11, are joined by two adhesive faces, so that a strong and secure union is effected.

As can be seen from FIG. 11, the combined tape flap made up of portions 27a and 24c extends downward a distance so as to be secured to the end of the coil form 23-this being designated by the numeral 23a in FIG. 11. The lengths of the combined tapes in their overlapped portions can be accurately regulated by means of the size of the insert or spacer 22, and particularly the cutting groove 29 therein.

As brought out previously, the tape 24 is sized in width slightly greater than the corresponding dimension of the tube 23. Tape 27 preferably is as wide as possible so as to reach to the radius of a corner of the wound coil. This can be particularly appreciated from a consideration of FIGS. 3, 8 and 9. In FIG. 3, the stepped tape guide or recess 25 is seen to be wider than the dimension A of the form 23. In FIGS. 8 and 9, the width of the tape again is seen to be wider than the corresponding dimension of the tube 23, particularly the outside dimension. Also, as mentioned previously, the wound coil forms of the invention are often employed in conjunction with laminated iron cores, and the provision of a tape that overlaps the outer dimension of the tube effectively prevents shifting of the windings, which might re sult in arcing or other undesirable operation. It will be appreciated that the inner tape 24 is important in precluding this undesirable operation, since it is interposed between the core 23 and the winding 26. It will also be appreciated that tape 27 may be applied on four sides, as well as the two illustrated.

The drawing also shows in greater detail a preferred form of spacer 23, wherein the spacer, as seen previously, is equipped with cutting grooves 29 and further is equipped with diagonal grooves 30 and 31, effective to receive the ends of the winding 26a and 2612. A projection 32 is provided with upwardly-tapered walls as at 32a to facilitate directing the winding ends into the grooves 30 and 31.

From the foregoing, it will be seen that the completed wound coil form includes two lengths of tape, each having a U-shaped configuration, with the ends of each being in overlapping relation to provide a bolster against lateral shifting of the random wound Winding 26. This bolster may include the flanges 22' if desired, the flanges 22' merely being applied loosely to the tubes 23 in the first instance.

The device and method herein described is exceptionally advantageous for high speed machine production, inasmuch as a plurality of forms can be simultaneously wound. The arbor equipped with spacers and coil forms can be assembled prior to introduction into the winding machine and, for that matter, may be equipped with the first length of tape 24 which is placed in conforming relation with the exterior of the spacer elements 22 and the coil forms 23. When the winding operation is completed, the second tape 27 is readily applied, and this tape is also effective to secure the Winding in place so that there is no unraveling thereof by virtue of the ends 26a and 26b becoming loose. A quick cutting operation is all that is required prior to disassembly or dismantling of the arbor and the elements mounted thereon. Depending on when the wire making up the winding is severed, the cutting operation may be performed either while the arbor is still installed on the winding machine or subsequent to its removal. As soon as the element, in the form seen in FIGS. 8-10, is removed from the arbor, the ends are readily folded into the configuration seen in FIG. 11 and the wound coil form is completed. Time may be saved by gang cutting after removal from the Winder and surfaces of the spacers may be recessed or coated with a material such as Teflon which will not allow the tape adhesive to adhere to the spacers. In this manner, the completed coils fall away from the spacers when disassembled.

While, in the foregoing specification, I have set forth a detailed description of an embodiment of the invention for the purpose of illustration thereof, many variations in the details herein given may be seen by those skilled in the art without departing from the spirit and scope of the invention.

I claim:

1. In a tape-confined inductive element, a tubular coil form having an axis for rotative winding thereof, a first length of tape adhesively secured to said form with the length thereof being disposed axially of the form and with the first tape ends extending away from said form, a winding about said form over the portion of the first tape secured thereto, said first tape ends extending along the sides of said winding and being folded on themselves, and a second length of tape, said second length of tape having the length thereof disposed axially of said form and being adhesively secured to a peripheral portion of said winding, with the ends of said second tape extending toward said form in adhesive, overlapping relation with the first tape ends, whereby three thicknesses of tape extend along the sides of said winding to provide a confining bolster to maintain the compactness of said winding.

2. The structure of claim 1 in which said form is generally rectangular in transverse section, said tapes being.

disposed over one of the sides of said rectangular transverse section, at least one of said tapes overlapping said one rectangular transverse section side.

3. The structure of claim 1 in which said form is generally rectangular in transverse section, said tapes being disposed over one of the sides of said rectangular transverse section, both said tapes overlapping said one rectangular transverse section side.

4. The structure of claim 1 in which said form has an axial length greater than the corresponding dimension of said winding whereby the overlapped ends of said first and second tapes are secured to the ends of said form.

5. The structure of claim 1 in which flange means extend transversely the axis of said form at the ends thereof, said tape ends being secured to said flange means.

6. In a tape-confined inductive element, a rectangular coil having an axis for rotative winding thereof and having at least one face adapted to adhesively receive a length of tape for confining a winding arranged on said form, a first length of tape adhesively secured to said face, with the first tape ends extending transversely away from said form, a winding about said form over the portion of the first tape secured thereto, said first tape ends extending along the sides of said winding and being folded on themselves to provide a double-walled bolster along the sides of said winding, and a second length of tape .5 adhesively secured to a peripheral portion of said Winding and with the ends of said second tape extending transversely toward said form in adhesive, overlapping relation With the folded end portions of said first tape, Whereby three thicknesses of tape extend along the sides of said winding to provide a confining bolster to maintain the compactness of said winding, each of said tapes having a Width greater than the corresponding dimension of said face, whereby said tapes overlap the corners of said form adjacent said face.

References Cited in the file of this patent UNITED STATES PATENTS Varley Dec. 17,

DoWd July 21,

Cahill Nov. 6,

Earhart Feb. 11,

FOREIGN PATENTS Germany Apr. 28,

Germany J an. 31, 

1. IN A TAPE-CONFINED INDUCTIVE ELEMENT, A TUBULAR COIL FORM HAVING AN AXIS FOR ROTATIVE WINDING THEREOF, A FIRST LENGTH OF TAPE ADHESIVELY SECURED TO SAID FORM WITH THE LENGTH THEREOF BEING DISPOSED AXIALLY OF THE FORM AND WITH THE FIRST TAPE ENDS EXTENDING AWAY FROM SAID FORM, A WINDING ABOUT SAID FORM OVER THE PORTION OF THE FIRST TAPE SECURED THERETO, SAID FIRST TAPE ENDS EXTENDING ALONG THE SIDES OF SAID WINDING AND BEING FOLDED ON THEMSELVES, AND A SECOND LENGTH OF TAPE, SAID SECOND LENGTH OF TAPE HAVING THE LENGTH THEREOF DISPOSED AXIALLY OF SAID FORM AND BEING ADHESIVELY SECURED TO A PERIPHERAL PORTION OF SAID WINDING, WITH THE ENDS OF SAID SECOND TAPE EXTENDING TOWARD SAID FORM IN ADHESIVE, OVERLAPPING RELATION WITH THE FIRST TAPE ENDS, WHEREBY THREE THICKNESSES OF TAPE EXTEND ALONG THE SIDES OF SAID WINDING TO PROVIDE A CONFINING BOLSTER TO MAINTAIN THE COMPACTNESS OF SAID WINDING. 